Determine file compression type and write C# code to decompress

I need to determine the file compression type used in a application's file format. I can provide any number of examples of the compressed and uncompressed files. Once the compression type is identified, I will need C# code written to reliably decompress the files. ## Deliverables The required deliverable is C# .NET source code with commented or documented classes, methods, and properties so that I may easily implement the code into my existing project. The source code must be written in C# and it is preferable to use .NET framework 2.0 and Visual Studio 2008. Any additional libraries or DLLs used to create the solution must be provided and available to compile into my existing project.